Class II division 2

By: Cezar Edward

Definition

Class II division 2 includes those

malocclusions where the upper central

incisors are retroclined. The overjet is

usually minimal, but may be increased.

Aetiology

Skeletal pattern

Soft tissues

Dental factors

1 Skeletal pattern

Class II division 2 malocclusion is commonly associated

with a mild Class II skeletal pattern, but may also occur in

association with a Class I or even a Class III dental base

relationship.

**Where the skeletal pattern is more markedly Class II the

upper incisors usually lie outside the control of the lower lip,

resulting in a Class II division 1 relationship, but where

the lower lip line is high relative to the upper incisors a

Class II division 2 malocclusion can result.

Fig. 10.1 A cross-sectional view through the study models of a patient

with a very severe Class II division 2 incisor relationship. Lack of an

occlusal stop allowed the incisors to continue erupting, leading to a

significantly increased overbite.+ reduced the vertical dimension

2 Soft tissues

The influence of the soft tissues in Class II

division 2 malocclusions is usually mediated

by the skeletal pattern.

Fig. 10.4 Typical Class II division 2

malocclusion with retroclination of

the upper central incisors. The lateral

incisors, which are shorter, escape

the effect of the lower lip and lie at an

average inclination, albeit slightly

mesiolabially rotated and crowded.

Fig. 10.5 Patient with bimaxillary

retroclination due to the action of the lips.

3 Dental factors

Crowding (smaller circumference arc) : The

upper laterals may rotate mesiolabially so

the centrals retroclines

crown–root angulation of upper centrals

could itself be due to the action of a high

lower lip line causing Deflection of the crown

of the tooth relative to the root after eruption.

Occlusal features

Centrals:retroclined

Laterals: are at an average angulation or are

proclined, depending upon their position relative to

the lower lip (if High lower lip =lateral retro)

in patients with a more severe Class II skeletal

pattern the overbite may be complete onto the

palatal mucosa. may cause ulceration of the

palatal tissues and in some patients retroclination

of the upper incisors leads to stripping of the labial

gingivae of the lower incisors

Management

1- increase overbite

2-reduce the inter-incisal angle to 135*

Fig. 10.11 If a Class II division 2 incisor relationship is to be corrected not only the

overbite but also the inter-incisal angle must be reduced to prevent

re-eruption of the incisors post-treatment: (a) Class II division 2 incisor relationship;

(b) reduction of the overbite alone will not be stable as the incisors will

re-erupt following removal of appliances; (c) reduction of the inter-incisal angle in

conjunction with reduction of the overbite has a greater chance of stability.

The inter-incisal angle in a Class II division 2

malocclusion can be reduced in a number of ways:

Fig. 10.12 Correction of a Class II division

2 incisor relationship by

reducing the overbite and torquing the

incisors lingually/palatally. Fixed

appliances are necessary.

Fig. 10.13 Correction of a Class II division

2 incisor relationship by

proclination of the lower labial segment.

Fig. 10.14 Correction of a Class II division 2 incisor relationship by an

initial phase involving proclination of the upper incisors, followed by

reduction of the resultant overjet with a functional appliance.

A combination of the above approaches.

Orthognathic surgery. This approach may

be the only alternative for

patients with a marked Class II skeletal

pattern and/or reduced vertical

skeletal proportions.

Approaches to the reduction of

overbite Intrusion of the incisors

Eruption of the molars

Extrusion of the molars

Proclination of the lower incisors

Surgery In adults “when it is significant”

Intrusion of the incisors

it is easier to move the molars occlusally

than to intrude the incisors into bone,

Fixed appliances are necessary

Eruption of the molars

This method requires a growing patient to

accommodate the increase in vertical

dimension

We put a flat plane on incisal edge of upper

Disocclusion the lower molars will

erupt in a good way so will increase the

vertical dimension

Extrusion of the molars

the major effect of attempting intrusion of the

incisors is often extrusion of the molars.

Proclination of the lower incisors

Fig. 10.16 Diagram to show spontaneous

proclination of the lower labial segment following

placement of a flat anterior bite-plane which

has reduced the overbite by eruption of the

lower molars.

Practical management

Fixed appliances

Functional appliances

Surgery

Key points

• Careful assessment of the aetiological factors contributing to the incisor

relationship and the degree to which they can be reduced or

eliminated is essential if treatment is to be successful

• The threshold for extractions in the lower arch is raised compared with other

malocclusions

• To increase the chances of a stable reduction in overbite, the inter-incisal angle

needs to be reduced and an adequate occlusal stop for the lower incisors created

The retention phase is particularly important in Class II division 2

malocclusions, with regard to the following:

• to prevent an increase in overbite

• to retain any de-rotated teeth, for example, the upper lateral incisors

• to maintain alignment of the lower labial segment, particularly if it

has been proclined during treatment

Fig. 10.20 An upper removable appliance used to expand the upper

arch and procline retroclined upper incisors prior to functional appliance

therapy.

Functional appliances can be utilized in the correction of Class II division 2

malocclusions in growing patients with a mild to moderate Class II skeletal

pattern

is known

as an ELSAA (Expansion and Labial Segment Alignment Appliance).

After anteroposterior correction with the

functional appliance, fixed

appliances are required to detail the

occlusion. If the lower incisors have

been proclined, the stability of their position

should be assessed and, if

doubtful, permanent retention should be

instituted

Reference